1. Field of the Invention
One embodiment of the present invention relates to a transistor, a semiconductor device, and a manufacturing method thereof.
Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter.
In this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A display device, a liquid crystal display device, a light-emitting device, a lighting device, an electro-optical device, a power storage device, a memory device, a semiconductor circuit, an imaging device, an electronic device, and the like may include a semiconductor device.
2. Description of the Related Art
In recent years, a transistor has been developed. A transistor is used in a semiconductor integrated circuit (IC chip) such as an LSI, a CPU, or a memory. A semiconductor integrated circuit is mounted on a circuit board, for example, a printed circuit board, to be used as one of components of a variety of electronic devices.
In recent years, a transistor including an oxide semiconductor in a semiconductor layer where a channel is formed (also referred to as an “OS transistor”) has attracted attention. An OS transistor is known to have an extremely low unintended current (also referred to as leakage current) between a source and a drain in an off state. For example, a low-power CPU utilizing a characteristic of low leakage current of the OS transistor is disclosed (see Patent Document 1).